Offline: always transfer image if lookup fails, always download drivers

[tstromberg]

This fixes two offline bugs. One found by user issue, and one found by adding an integration test for it.

• If reference lookups fail due to lack of external connectivity or lack of a locker Docker daemon, transfer the images anyways. The integration test simulates this by providing a bad proxy and docker environment.

• If --download-only is specified, we were not downloading drivers, so the subsequently airgapped run would fail.

Fixes #6103 #6116

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: tstromberg

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[codecov-io]

Codecov Report

Merging #6111 into master will decrease coverage by <.01%.
The diff coverage is 0%.

@@            Coverage Diff            @@
##           master   #6111      +/-   ##
=========================================
- Coverage    36.7%   36.7%   -0.01%     
=========================================
  Files         113     113              
  Lines        8355    8356       +1     
=========================================
  Hits         3067    3067              
- Misses       4887    4888       +1     
  Partials      401     401

Impacted Files	Coverage Δ
pkg/minikube/machine/cache_images.go	4.34% <0%> (-0.04%)	⬇️
cmd/minikube/cmd/start.go	22.7% <0%> (+0.03%)	⬆️

[tstromberg]

/ok-to-test

[minikube-bot]

All Times minikube: [ 127.055862 115.152244 125.869987]
All Times Minikube (PR 6111): [ 126.210117 125.469309 125.048183]

Average minikube: 122.692698
Average Minikube (PR 6111): 125.575870

Averages Time Per Log

+----------------------+-----------+--------------------+
|         LOG          | MINIKUBE  | MINIKUBE (PR 6111) |
+----------------------+-----------+--------------------+
| minikube v           |  0.281601 |           0.284042 |
| Creating kvm2        | 47.672722 |          47.207873 |
| Preparing Kubernetes | 48.597293 |          51.779932 |
| Pulling images       |  2.848315 |           3.417374 |
| Launching Kubernetes | 20.185430 |          19.937815 |
| Waiting for cluster  |  3.057201 |           2.897314 |
+----------------------+-----------+--------------------+

[minikube-bot]

All Times minikube: [ 121.223707 123.956422 119.502534]
All Times Minikube (PR 6111): [ 109.120621 122.108481 120.232857]

Average minikube: 121.560888
Average Minikube (PR 6111): 117.153986

Averages Time Per Log

+----------------------+-----------+--------------------+
|         LOG          | MINIKUBE  | MINIKUBE (PR 6111) |
+----------------------+-----------+--------------------+
| minikube v           |  0.253499 |           0.243622 |
| Creating kvm2        | 45.905812 |          45.297773 |
| Preparing Kubernetes | 49.692484 |          47.528081 |
| Pulling images       |  3.203871 |           2.624211 |
| Launching Kubernetes | 19.899237 |          18.855639 |
| Waiting for cluster  |  2.559773 |           2.560995 |
+----------------------+-----------+--------------------+

[priyawadhwa]

lgtm

[minikube-bot]

All Times minikube: [ 124.102523 119.469092 124.420490]
All Times Minikube (PR 6111): [ 123.091943 122.003560 124.030090]

Average minikube: 122.664035
Average Minikube (PR 6111): 123.041865

Averages Time Per Log

+----------------------+-----------+--------------------+
|         LOG          | MINIKUBE  | MINIKUBE (PR 6111) |
+----------------------+-----------+--------------------+
| minikube v           |  0.250627 |           0.245423 |
| Creating kvm2        | 46.270367 |          45.986086 |
| Preparing Kubernetes | 49.780346 |          50.386461 |
| Pulling images       |  2.967455 |           2.901823 |
| Launching Kubernetes | 20.632335 |          20.396361 |
| Waiting for cluster  |  2.715480 |           3.081527 |
+----------------------+-----------+--------------------+